The present invention relates to cleaning equipment for tubes and piping and, in particular, to high-pressure water spray systems for cleaning the bores of tubes mounted in a variety of equipment, such as heat exchangers, falling pressure evaporators and the like.
Industrial piping systems of all types frequently require cleaning. A problem especially common to heat exchangers and evaporators is that over time the bore and exterior walls of the heat exchange tubes develop corrosion, scale and other undesired residue. The buildup of residue decreases and/or generally adversely effects the heat transfer efficiencies. Operating costs for fuel, in turn, increase.
Periodic maintenance is thus required to clean the tubes. Frequently the equipment must be taken off-line during maintenance. Such maintenance can be performed by plant personnel or outside contractors who are specially trained and use special purpose equipment to perform such tasks. It is desirable that any down time be minimized. The task is typically performed manually and is therefore costly and time consuming, especially for large heating and cooling plants.
A variety of techniques and types of equipment have been developed to clean the interior and exterior surfaces of pipes and particularly heat transfer tubes. Soot blowing and chemical shocking are two techniques. Another technique is to individually direct equipment into each tube to mechanically dislodge the residue from the tube walls. Some of the latter equipment uses rigid lances that either rotate and/or have rotating blades. U.S. Pat. No. 5,579,726 discloses a lance-based assembly that directs streams of high-pressure water to effect the cleaning. The latter system supports a rotating and axially directed lance from a frame that can be aligned to each tube.
High-pressure spray systems are also known that direct streams of water from a spray hose into each tube. Jetting Systems and Accessories, Inc. sells one such system under the brand name xe2x80x9cFLEX LANCERxe2x80x9d. Another system is sold by Gardner Denver Water Jetting Systems, Inc., Houston, Tex. under the name xe2x80x9cVxe2x80x9d Drum Rotary Line Cleaner. The latter system provides a high-pressure hose and spray nozzle that are rotated and axially directed under power. Hose movement is directed with a hand-operated air controller and a pinch roller assembly that controls axial hose movement. Rotational movement is controlled via a separate motor. The hose is collected and dispensed from a rotating V-shaped spool or drum. Although offering advantages, the efficiency of the latter system is severely restricted by vibrations that occur due to unbalanced conditions that can occur at the equipment during typical use. Extreme vibrations have particularly been experienced at speeds approaching 60 rpm, which severely limits the utility of the equipment.
The present invention was developed to provide a more efficient high-pressure spray system. The assembly provides a hose mounted spray head that can be operated at rotational speeds in the range of 60 rpm to 850 rpm. Axial speeds in the ranges of 1 foot per minute to 80 feet per minute are also possible. At a nominal rotary speed of 300 rpm and an axial speed of 60 feet per minute the assembly is able to clean a typical 36-foot tube in one-fourth the time as the foregoing equipment.
The assembly is constructed to provide optimal balance along the entire drive train. The assembly also cleans the exterior surface of the spray hose as it is dispensed and collected from a driven spool or reel assembly. The reel assembly stacks the hosing in a tapered coil that is balanced to the longitudinal drive axis of the hose drive train. The hub of the reel assembly can be adjusted to accommodate different lengths and diameters of hose.
It is accordingly a primary object of the invention to provide a high-pressure tube cleaning assembly wherein a spray hose and spray nozzle can be directed at high rotational and axial rates by the assembly as the nozzle is directed through each tube being cleaned.
It is a further object of the invention to provide an assembly that includes a rotationally driven hose reel that arranges the spray hose in a fashion that avoids unbalancing the equipment relative to a longitudinal, rotational drive axis.
It is a further object of the invention to provide a hose reel having a conically tapered, hose collection hub mounted adjacent to a concentric outer cage and on which hub the hose is stacked in coils concentrically aligned to the longitudinal drive axis.
It is a further object of the invention to provide a hose cleaning assembly that cleans the hose as it is dispensed and collected.
It is a further object of the invention to provide a rotary mounted, air-controlled hose drive assembly having four polyurethane pinch-type drive wheels that axially direct the hose along the assembly""s longitudinal drive axis and that is rotationally balanced relative to a hose reel.
It is a further object of the invention to provide a drive axle at the hose reel that is coupled to the hose drive assembly and from which axle a layering arm extends that aligns the hose relative to an adjustable hub at the hose reel.
It is a further object of the invention to provide a hose collection hub wherein the diameter and taper of the hose collection hub can be adjusted relative to the outer cage and center drive axle.
The foregoing objects, advantages and distinctions of the invention, among others, are obtained in the following disclosed tube cleaning assembly that has been particularly adapted for use in cleaning heat exchangers and falling tube evaporators. The invention can be adapted to other applications wherein the tool head is coupled to a high-speed, rotationally and axially directed supply conduit.
The subject tube cleaning assembly provides a mobile framework that attaches to on-site air and water supplies. The assembly includes a number of subassemblies that are concentrically aligned along a longitudinal drive axis to direct a high-pressure hose and spray head. The subassemblies are mounted to rotate in controlled synchrony at a number of pillow block bearings.
At a fore end, the hose and orifice containing spray head are directed through a hose cleaning subassembly that washes the hose with a low-pressure spray. The hose is axially directed to and fro with an air-controlled hose drive assembly. A hand-operated valve directs air to an air swivel and a pair of drive motors. Drive power is applied to a pair of driven gears and chains to follower gears attached to four polyurethane pinch wheels that abut the hose. Spring tensioners control the wheel-to-hose pressure and are able to axially direct the hose at speeds of 1 to 80 feet per minute.
The hose drive is coupled to a hose collection reel via a motor driven reel axle. A layering arm extends from the axle and directs the hose onto an adjustable hub at the reel. The hose is preferably stacked in a single layer. A swivel at the opposite end of the reel axle supplies high-pressure water in the range of 3,000 psi to 50,000 psi to the hose.
The diameter of the hub at the hose reel can adjusted relative to an outer cage. The layering arm and hub cooperate to stack the hose in concentric layers relative to the longitudinal drive axis of the assembly to assure a balanced loading. The reel, axial hose drive and hose cleaner assemblies can be operated at rotational speeds in the range of 60 rpm to 650 rpm. The assembly is thereby able to clean tubes from xc2xd to 6-inch diameters at rates of 1 to 80 feet per minute.
Still other objects, advantages, distinctions and constructions of the invention will become more apparent from the following description with respect to the appended drawings. Similar components and assemblies are referred to in the various drawings with similar alphanumeric reference characters. Various features of the invention may also be configured with other features in different combinations. The description should therefore not be literally construed in limitation of the invention. Rather, the invention should be interpreted within the broad scope of the further appended claims.